App Kit SDK: Earn

The App Kit SDK includes the Earn capability that lets you offer opportunities to earn USDC and EURC. Vaults are powered by underlying DeFi lending protocols. Earn handles vault discovery and share-to-asset conversion, so you don’t need to integrate each vault contract directly. Earn is available for USDC and EURC on Arc.

How it works

When you deposit USDC into an Earn vault, you receive vault shares. The shares appreciate over time as the underlying lending protocol generates returns. To exit, you redeem your shares back to USDC, which by then is worth your deposit plus any returns from the protocol. Earn is non-custodial: deposited USDC lives in the vault contract, and integrators choose which vaults to deposit into.

Quick look

This code snippet fetches vault details and deposits into a vault:

TypeScript

// Fetch vault details
const { vaults } = await kit.earn.exploreVaults({
  chain: "Arc_Testnet",
  sortBy: "apy",
});

// Deposit into the first vault
const result = await kit.earn.deposit({
  from: { adapter, chain: "Arc_Testnet" },
  vaultAddress: vaults[0].vaultAddress,
  amount: "10.00",
});

For a complete end-to-end flow, follow the quickstart.

API key

Earn accepts an optional Circle API key obtained from the Circle Console. Pass one as apiKey in the operation config. Without one, requests share a rate limit. Production traffic typically needs a key to avoid hitting it. For a restricted key, select the “App Kits” product permission when creating the key. API keys are environment specific. Testnet and mainnet each need their own key. Keep the API key server-side. The App Kit SDK rejects an API key passed from a browser context.

Installation

Install the App Kit SDK to use Earn. If you only need Earn and don’t want to install the full App Kit SDK, install the standalone Earn Kit for your preferred adapter:

Viem
Ethers
Circle Wallets

npm install @circle-fin/earn-kit @circle-fin/adapter-viem-v2 viem

yarn add @circle-fin/earn-kit @circle-fin/adapter-viem-v2 viem

npm install @circle-fin/earn-kit @circle-fin/adapter-ethers-v6 ethers

yarn add @circle-fin/earn-kit @circle-fin/adapter-ethers-v6 ethers

npm install @circle-fin/earn-kit @circle-fin/adapter-circle-wallets

yarn add @circle-fin/earn-kit @circle-fin/adapter-circle-wallets

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Onramp

Earn

Borrow

App Kit SDK: Earn

How it works

Quick look

API key

Installation

​How it works

​Quick look

​API key

​Installation

How it works

Quick look

API key

Installation